Headlight tester



Dec. 3, 1946. g, GHQ M S 2,'411;s79

HEADLIGHT TESTER Filed June 18, 1940- 9 Sheets-Sheet 1 INVINTOR HERBERT G. HOLMES ATTORNEY H. G. HOLMES HEADLIGHT TESTER Filed June 18, 1940 INVENTOR TGHOLMES HERAER as B ATTORNEY 9 Sheets-Sheet 2 Dec. 3;= 1946.' H. s. HOLMES I HEADLIGHT TESTER v Filed-'June 18. i940v 9 Shuts-Sheet 3 MNN V mvzm'oa HERBERT 6. HOLMES l "69%- QKW ATT-ORNY Dec. 3, 1946. HOLMES 2,411,879

HEADLIGHT TESTER Filed Jun-e 1 4 1940 9 Sheets-Sheet 7 HERBERfGHaLm ATTORNEY Dec. 3, 1946.

H. G. HOLMES I-IEIADLICYI IT TESTER Filed June 18, 1940 9 Sheets-Sheet 8 INVENT OR HERBERT aha/. 5.:

ATTORNE Dec. 3,1946. H. e. HOLMES HEADLIGHT TESTER Filed June 18; 1940 9 sheets-sheet 9 Patented Dec. 3, 1946 HEADLIGHT "rns'rn n Herbert Glenn Holmes, Lansing, Mich., assignor to Food Machinery Corporation, San Jose, Calif., a corporation of Delaware Application June 18, 1940, Serial No. 341.178

31 Claims. (CI. 88-14) This invention relates to apparatus for testing the headlights of automobiles and particularly to the type of apparatus employing a light-sensitive cell in the testing instrument.

One of the objects of the invention is to provide a headlight testing instrument adapted to be placed in the beam of a headlight to determine the angular direction of the beam with respect to the line of travel of the vehicle.

Another object of the invention is to provide a headlight testing instrument adapted to be placed in the beam of the headlight to measure the intensity of the beam and to employ the measurement of intensity obtained for determining the angular direction of the beam with respect to the line of'travel of the vehicle.

Another object of the invention is ,to provide a headlight testing instrument adapted to be placed in the beam of the headlight to determine the direction of the beam by measuring thevertical and horizontal inclinations of the beam to the of travel of the vehicle.

Anotherobject of the invention is to provide an improved means for measuring the vertical inclination of the beam to the line of travel.

Another object of the invention is to .provide an apparatus for determining the horizontal inciination of the beam.

Another object of the invention is to provide a means 'for'contacting the lens of the headlight which will serve as a universal pivot on which to adjust the instrument axis in a preliminary step of the testing operation.

Another object of the invention is to provide a headlight testing instrument which can be employed either as aportable hand instrument or in tion has been embodied.

In the drawings:

Fig. 1 is a plan view of the testing instrument.

Fig. 2 is a right side elevation.

Fig. 3 is a left side elevation.

Fig. 4 is an elevation of the front end of .the instrument.

Fig. 5 is a vertical longitudinal section taken as indicated by the arrows 5-5 in Fig; 1.

Fig. 615 a fragmentary sectional view taken as indicated by the arrows [-0 in Fig. 5.

Fig. '7 is a fragmentary sectional view taken as indicated by thearrows '1 in Fig. 5. v

Fig. 8 is a vertical transverse section taken as indicatedby the arrows 8-8 in Fig. 1..

Fig. 9 is a fragmentary elevation taken as indicated by the arrows 9-9 in Fig. 5.

line

2 Fig. '10 is a fragmentary elevationtaken as indicated by the arrows Iii-l0 in Fig. 5.

Fig. 11 is a vertical longitudinal section taken as indicated by the arrows I l-i I in Fig. l.

Fig. 12 is a fragmentary section taken as indicated by the arrows l2-l2 in Fig. 8.

Fig. 13 is a fragmentary section'taken as in dicated by the arrows l3-I3 in Fig. 8.

Fig. 14 is a. fragmentary section taken as indicated by the arrows i l-44 in Fig. 11.

Fig. 15 is a perspective view of the pendulum rod which is used as a marker.

Fig. 16 illustrates the manner in which the marker is positioned in front of the headlight.

Fig. 1'7 illustrates the method of measuring the horizontal inclination by-means of the in-'- strument positioned in front of one headlight and the marker in front of the other.

Fig. 18 is a vertical section through the optical finder employed to determine the horizontal inclination of the beam.

Fig. 19 is a horizontal section therethrough taken as indicated by the arrows i9-l9 in Fig. 18.

Fig. 20 is a plan view with parts broken away of the finder in a different position.

Fig. 21 is ahorizontal section through the instrument, showingthe means for adjusting the finder.

. Fig. 22 is awiring diagram.

Fig. 23 illustrates the manner of using the headlight testing apparatus when the instrument is mounted .on a mobile stand.

Fig. 24 is a right side elevation of the instrument mounted on the stand.

Fig. 25 is a plan view thereof.

Fig. 26 is a fragmentary plan view of the instrument support provided in the stand.

In order to facilitate an understanding of the invention, a preliminary explanation will be given in which the general arrangement and use of .the

instrument will be briefly set forth.

The headlight testing instrument comprises certain. mechanism presently to be described in detail, which is contained in a case Ill (Fig. 1). The case is provided with a handle ll mounted on the left side 45 and a handle 42 mounted on the right side 46 thereof. When used as a portable instrument the operator holds the instrument in his handsby means of the handles ll, 42. The instrument is placed in the beam of the headlight to be tested by pressing the contact 43. which is preferably made of rubber. against the lens of the headlight.

Rays from the beam of the headlight are admitted to the interior ofthe instrument through 3 a plurality of orifices numbered 5| to 58 (Fig. 4) located about the contact 43 in the front wall 44 of the case 40.

The intensity of the light admitted to the instrument from the beam is registered on the meter 59 (Fig. 1) which is provided with a pointer 60 that moves over a scale 6I calibrated in candle power. A switch 62 mounted on the right side 46 of the case 40 governs the range of the meter 59, as will presently be described,

Holding the contact 43 against the lens of the headlight the operator manipulates the instrument with a universal movement, that is, left and right, and up and down, until he finds the position of the instrument at which tehe maximum reading is obtained on the intensity meter 59. The longitudinal axis of the instrument which passes through the center of the contact 43 is then substantially in coincidence with the axis of the beam and in parallelism with the rays thereof. In order to determine the direction of the beam, he turns the knob 93 with his left.

thumb to measure the vertical inclination, and he turns the knob 64 with his right thumb to measure the horizontal inclination. When the knob 63 has been properly adjusted, as will presently be described, the operator reads the vertical inclination by means of the pointer 85 on the scale 58, and when the knob 94 has been properly adjusted, he reads the horizontal inclination by means of the pointer 61, which has two cross hairs 68 that cooperate with two sets of scales, one for the right hand lamp, the other for the left hand lamp. These scales are marked on an arcuate strip 69-which is attached by means of screws I to the top of the case 40. The upper scales II are calibrated in degrees, and the lower scales I2 are calibrated in inches at twenty-five feet distance, so that the horizontal inclination may be measured either in angular degrees or in distance.

Proceeding now with a detailed description of the instrument mechanism, the rubber contact 43 (Fig. has a press fit in a metalcup I3 which is mounted on the front wall 44 of the case 40 by means of a spacer bracket II and a screw I5 which passes through the cup I3 and the bracket I4 and is threaded into the front wall 44 at 15. It will be recalled that there are a series of apertures 5I to 58 (Fig. 4) in the front wall 44. The top and bottom apertures 5| and 55 appear in Fig. 5. The longitudinal or reference axis of the instrument or tester is indicated by the center line 11.

Rigidly mounted within the case 40 and accurately positioned normal to the reference axis 11 is the diaphragm I8. The diaphragm I8 (Fig. 8)

has a series of apertures 8I to 98 which are located in longitudinal alignment with the apertures ii to 58 (Fig. 4), and are smaller than the apertures 5| to 58. The top and bottom diaphragm apertures BL. 85 appear in Fig. 5. A transparent glass plate 99 is mounted on the front of the diaphragm I8 and covers the apertures therein. A second diaphragm 90 is rigidly mounted in the rear end of the case 40 so as to be accurately positioned normal to the longitudinal axis 11. The diaphragm 90 (Fig. 9) has a series of apertures 9| to 98 which are the same size as the apertures inthe front diaphragm l8 and are located in longitudinal alignment therewith. The purpose of the aligned apertures in the two diaphragms I8 and 90 is to select parallel rays from the beam of the headlight.

When the instrument axis TI is posltlolwtl sub- 4 stantially coincident'with the axis of the beam and parallel to the rays thereof, parallel rays such as 99 and I00 (Fig. 5) will enter the apertures 5|, 55 in the front wall 44 of the case, pass through the apertures 8I and 85 in the front diaphragm I8 .and then pass through the apertures 9I, 95 in the rear diaphragm 90. It will be apparent that .this only occurs when the instrument is positioned so that its axis 11 is parallel to the rays 99,

100, because if the instrument axis 11 is out of parallelism with the rays of the beam, rays such as 99, I00, although they might enter the apertures BI, 55, would not pass through the apertures 9| and 95. v

A series of planar mirrors IM to I08 (Figs. 5, 9, and 10) is mounted on the rear side of the rear diaphragm 90 with the mirror IOI behind aperture 9|, mirror I02 behind aperture 92, mirror I03 behind aperture 93, and so on. Bowed spring clamps I09 are fastened to the diaphragm 90 by means of screws H0. The ends of each clamp bear against the backs of 'two adjacent mirrors. In this manner the mirrors are clamped against adjusting screws I I2 which are threaded into the diaphragm 90, there being three adjusting screws II2 for each mirror.

The screws H2 are adjusted to position the mirrors so that they will reflect the rays into a light-sensitive cell I20. For example, in Fig. 5 the mirrors IOI, I05 are adjusted so that they reflect the rays 99 and I00 in the directions indicated by the lines I I3, I I4 which converge at I I5. A shield I2I having an aperture I22 is placed over the window of the light-sensitive cell I20, The shield I2I serves to exclude from the lightsensitive cell all rays reflected thereon except rays such as 99 and I00 which enter the instrument parallel to its axis 11. It will be noted that the focal point II5 of the reflected rays lies on the instrument axis 11, so that rays from the beam, such as 99 and I00, are not reflected onto the light-sensitive cell I20 until the instrument axis 11 is brought into parallelism with the rays of the beam.

The light-sensitive cell I20 is rigidly mounted on the front diaphragm I8 by means of two bosses I23, I24 (Fig. 21) into which screws I25, I26 are threaded. The light-sensitive sell I20 (Fig. 5) is of the blocking-layer type, the metallic elements of which create an electromotive force when exposed to light. The electrical response of the cell is measured by a sensitive meter 59. Wires I21, I28 (Figs. 5 and 8) are connected to the terminals I29, I30 of the cell I20. The wire I21 leads to the terminal I3I of the meter 59, while the wire series with the meter 59 and the cell I20, or to cut the resistance I33 out of the circuit. The purpose of this arrangement is to give the meter 59 a high and low range depending on whether the resistance I33 is cut in or out of the circuit by the 0 switch 62.

Thus, when the instrument axis 11 (Fig. 5) is brought into line with the beam, parallel rays pass through the apertures inthe two diaphragms I8, 90 and are reflected by the mirrors through the aperture I22 into t e light-sensitive cell I25, and the meter 59 (Fig. 1) registers the intensity ofthe light. Conversely, when a maximum reading is obtained on the meter 58, it is an indication that the instrument axis has been positioned in line with the beam and the direction of the beam is, in this way, determined.

The mechanism by which the vertical and horizontal angles of inclination of the beam to the line of travel of the vehicle are measured will now 6 outside the side wall 45. Ascrew I 18 which is slidable in a slot I85 (Figs. 3 and 12) formed in the wall 45 is threaded into the knob I15. The

' screw I19 passes through a member I8I which of the case. A pinion I45 is secured on the shaft I44 for rotation by the knob 58. .A rack I41 (Fig. 11) meshes with the pinion I45, Guide plate I45 is rigidly attached to the rack I41 and has a slot I49 therein' through which the shaft I 44 passes so that the rack I41 is guided for sliding movement with respect to the shaft I44 and is maintained in mesh with the pinion 145. The forward end of the rack I41 is pivotally connected at I55 to the pointer 55. The foot of the pointer 55 is pivotally supported at I5I on the bar I52 which is provided with two slots I 58, I54 to receive screws I55, I55 which are threaded into bosses I51, I58 (Fig. 21) formed on the side wall 45 of the case. By loosening the screws I55, I55 the has pins I82,I85 engaging in apertures I54, I85 in the scale plate "I. In order to adjust the scale 55 the operator unscrews the knob I18 from the screw I19 a suiilcient amount to permit him to move the knob .back and forth, thus causing the scale plate Hi to slide on the sleeves I55,

I51. When the scale 55 has been positioned as desired, the knob I18 is tightened to hold the adjustment. This scale adjustment is employed by the operator to correct the zero position when the automobile is not standing on a true horizontal .surface at the time the headlights are being tested.

The operator makes the corrective adjustment by placing the instrument on a part of the car which is known to be level, such as the running board or the floor of the trunk compartment,

- and levelling the spirit level I55 (Fig. 1) by turnbar I52 may be moved forwardly or rearwardly to position the-pivotal center I5I of the pointer 55. This adjustment is usually made at the factory for a purpose presently to be described. A lever I59 (Figs. 8 and '11) is connected at I55 to the pointer 55. The lever I59 is rotatably mounted by means of a pin I5I ,(Figs. 1i and 13) secured thereto and having bearing in an aperture I52 in a member I53 which is rigidly mounted on the s de wall 45 by means of screws I 54, I55 which extend through spacing sleeves I55, I51. It will beunderstood that the member I53 is fixed but the pin 'I5I is free to rotate in the aperture I52, thus providing a fulcrum for the lever I59.

The upper end of the lever I59 (Figs. 11 and 14) has a spirit level I58 rigidly secured thereto.

By means of the linkage construction Just described, the rack I41 (Fig. 11) oscillates the pointer 55 and rocks the spirit level I55 on its fulcrum I5I. The'construction of the linkage is such that while the movement of the pointer is proportional to the movement of the spirit level, the movement of the pointer is greatly multipl ed to facilitate obtaining a reading on the scale 55. Also, the movements are in opposite directions;

that is, whenthe rack I41 moves the pointer 55 ing the knob 53. When the-bubble I59 is between the centering lines I85, I81; which are marked on the glass tube of the level, the pointer is opposite the mark 55' at the center of the bubble if the surface on which the automobile is standing is horizontal. However, if the surface is inclined to the horizontal, thepointer 55 will not be opposite the mark 55' at the center of the bubble when the bubble is centered between the lines I85, I81. The operator is able to correct for this condition by loosening the knob I18 and shifting the scale 55 until the zero point is opposite the pointer 55. He then locks the scale in this corrected position by screwing in the knob I 18.

After this preliminary adjustment the operator places the instrument in front of one of .the headlights, holding it by the handles 4|, 42,- and presses the contact 49 against the center of the.

employing the flexible contact 49 as a universal pivot, until he finds the position Of the instrument at which a maximum reading is obtained on the meter scale 6|. When the meter indicates that the instrument'axis has thus been brought into line with the beam, the operator holds the instrument stationary and turns the knob 55' with his thumb, .so as to return the bubble I59 to its central position between the centering lines I85,

to the left in Fig. 11, the level I55 is rocked to the right. Th s further facilitates making the adiustment in that the pointer moves in the same direction as the bubble I59 of the level I58,

The scale 55 (Fig. 11) is arcuate in shape and is secured at its outer edge I18 (Fig. 14) to a vertical plate "I having slots I12, I18 (Fig. 13) through which the spacing sleeves I55, I51 extend. Springs I14, I15 coiled about the sleeves I55, I51 bear against washers I 15, I11 to apply friction to the plate "I to hold the plate "I in its adjusted position onthe sleeves I55, I51.

It will be understood that the plate I" is sup-' ported by means of these sleeves but is slidably adjustable thereon by reason of the slots I 12, I18. In order to impart this sliding adjustment to the scale plate "I (Fig. 12) a knob I 15 is provided I81. After this has been done the position of the pointer 55 on the scale 55 is read, and this readingis an indication of the vertical inclination of the beam to the line of travel of the automobile.

As previously mentioned, the adjustment of the pointer 55 (Fig. 1) is facilitated by the fact that the pointer moves in the same direction as the bubble I59 so that, for example, when the instrument has been positioned to obtain the maximum reading on themeter 59, if the bubble I 58 is rearward .of the centering line I81, the operator turns the knob 53 to move the pointer 55 forwardly, and in so doing moves the bubble forwardly. As can be seen in Fig. 11, when the pointer; 55 is rocked forwardly, that is, tothe right in this view, the lever I58 is turned counterclockwise on its pivot I5 I, thus causing the bubble I58 to move to the right or forwardly in the same direction as the pointer 55. Due to this linkageconstruction, there is only one position of the 7 the bubble I88. This is the true horizontal position, that is, when the axis of the instrument is horizontal. The pointer is adjusted to this position at the factory by loosening the screws I55, I58 and sliding the bar I52 forwardly or rearwardly when the instrument is placed on a surface which is known to 'be horizontal.

The method and apparatus for measuring the horizontal inclination of the headlight beam will now be described. The method consists in establishing a plane represented by the dot-dash line I88 (Fig. 17 normal to the lines of travel of the vehicle, such as the lines represented at I88 and I82, and then measuring the angle I80 which thebeam direction I8I makes with the established transverse plane I88. The line of travel I82 normal to the plane I88 and passing through the contact 43 forms with the instrument axis 11, which coincides with the beam direction I8I, an angle I83 which is the complement of the angle I80. The angle I83 is the horizontal inclination of thebeam to the line of travel of the vehicle. In other words, to determine the horizontal inclination of the beam to the line of travel, the

following steps aretaken: the imaginary plane normal to the line of travel is established. The

horizontal angle which the beammakes with the imaginary plane is determined. Finally, the complement of the angle between the beam and the plane is measured, because this complementary angle equals the horizontal angle between the beam and the line of travel.

The apparatus for establishing the imaginary reference plane I88 is constructed as follows. As shown in Fig. 1'7, when testing one headlight with the instrument, a marker device indicated generally at I84 is placed in front of the other headlight. The device I84 (Fig. 16) includes'a pendulum rod I85 which is suspended in a vertical position at.a predetermined fixed distance K in front of the lens I85 of the headlight. Preferably the rod I85 is chromium plated so that it will be illuminated by the beam from the headlight. Referring to Fig. 15, where the marker device I84 is shown in perspective on V an enlarged scale, the pendulum rod I85 is pivotally mounted at I81 in a support I88 having a bearing portion I88 bored to receive a rod 200. The portion I88 is rigidly secured at 20I to a tube 202 which is rigidly secured at 203 to a bearing 204 formed integrally with a bar 205 having guide lugs 205 for a member 201 which can be adjusted vertically by sliding on, the bar 205. The member has two guide lugs 208 which embrace .the bar 205. The foot of the member 201 extends forwardly toward the headlight and is provided with a contact 208 which is brought into engagement with the lens I85 as shown in Fig. 16 The rod 200 which is slidable in thebearings I88, 204, has an eye 2I0 formed at its forward end. The eye portion .2I fits into a circular groove 2 formed in theperiphery of a disc 2I2 so that the disc 2I2 is freely rotatable within the eye member 2I0 about a horizontal axis. The disc 2I2 has a bore. 2I3 coincident with its axis of rotation, and the bent rod 2 havin down! wardly inclined ends 2I5, 2I5 is supported for rotation in the bore 2I3. Rubber suction cups 2", 2I8 are pivotally mounted at 2I8, 220 on the ends of the bent rod 2'I4.

These suction cups are pressed into engagement with the headlight as shown in Fig. 16 or into engagement with the fender as shown in Fig. 23, depending on the manner in which the headlight is mounted. The tube 202 (Fig. 16), together with the bearings I88, 204,'is slid along the rod 200 to bring the contact 208 against the lens I85. The member 201 is vertically adjusted on its supporting bar 205 tobring the contact 208 to the center of the lens. The tube 202 is then adjusted on the rod 200 until the pendulum I85 is at a vertical position, as indicated by the top end 221 of the rod being opposite the pointer 222. By this means the rod I85 is positioned vertically in front of the opposite headlight and at a predetermined fixed distance in front of the lens thereof. It will be noted that the horizontal distance K from the contact 208 (Fig. 16) to the rod I85 remains constant on account of the fact that the members I88 and 205 are rigidly joined together by means. of the tube 202, which is welded to the bearings I88 and 204, so, that the assembly I88 to 205is a unit. The vertical axis 223 (Fig. 5) of an optical finder 224 in the instrument is located this same distance K from the contact 43, so that" the imaginary reference plane is established by sighting the marker I85 through the finder 224 because they are disposed at equal distances in front of the two headlights.

The finder 224 comprises a laterally extending tube 225 (Fig. 18) having a lens 220 in the outer end thereof. The tube 225 is formed integrally with the mounting 226" which has a vertically extending cylindrical portion 22'1rotatable in a bore 228 in a boss 230 .formed in the top of the case 40. A collar 23.I is secured to the cylindrical portion 221 by means of a set screw 232. The hub 233 of the pointer 51 (Fig. 1) is interposed between the bottom of the collar 23I and the top of the boss 230. The pointer 51 (Fig. 5) has a spring detent 234 attached thereto which engages in the notch 235 (Figs. 5 and 19) formed in the underside of the collar 23I. This connection between the hub of the pointer and the collar of the finder is made detachable for a purpose presently to be described. As long as the detent 234 is seated in the notch 235 the pointer 51 and the collar 23I rotate in unison about the axis 223 of the finder. An adjustable eye piece 235 having a ground glass screen 231 mounted in the lower end .thereof is slidably mounted within the cylindrical portion 221.

which are 180 apart.

And a mirror 238 is clamped by means of screws 238 to the mounting 225'. There is a window 240 in the sidewall 45 of the case. By moving the eyepiece up and down the operator can 5 focus the image of the pendulum rod I85 which is reflected from the mirror 238 on the ground glass 231;

In order to test both headlights, the finder 224 is adjustable to right and left hand positions, The position shown in Figs. 18 and 19 is the position of the parts when the left hand headlight is being tested, in which case the tube 225 points to the right and the image of the rod is received through the right hand 5 window 240. When the right hand headlight is led 23I (Fig. 19) has a semi-circular depression being tested, as shown in Fig. 1'1, the tube 225v is swung around to point out of the left hand window I, as shown in Fig. 20. This is made possible by the following construction. The col- 242 formed therein into which extends a pin 243 having a press fit in an aperture 244 (Fig. '18) in the boss 230. The pin 243 serves as a stop pin. The semi-circular depression 242 permits the collar 23I to be rotatedthrough clock- 'wis'e'in Fig.1!) but prevents counterclockwise rotation for more'than a limited amount. Diametrically oppositethe notch 255 in the collar 25I is a similar notch 245 in which the detent 254 is adapted to seat after the collar 23I has been rotated 180. The detent and the pointer 51 are limited in their movement by reasonof the fact that th hub 255 of the pointer 51 has an opening 245 through which the pin 245 extends, and the limits of'movement of the pointer 51 are determined by contact of either of=the two edges 241 with the pin 245. To change the finder from the right-hand position (Fig. 19) to the left hand position-(Fig 20) the operator turns the collar- 25I clockwise. When the wall 241 of the opening 245 in the hub 255 contacts the pin 245, the pointer 51 is stopped and the detent 234 is disengaged from the notch 255. The operator continues to turn the collar 25I for 180 until the notch 245 receives thedetent 254, thus again coupling the pointer to the finder for use in the left hand position (Fig. 20) The pointer has two cross hairs 55 for cooperation with theright and left han scales (Fig. 1) as previously described.

The means for adjusting the pointer 51 by means of the knob 54 will now be described. The knob 54 (Fig. 21) is secured by means of a set screw 241 to a shaft 245 rotatably' supported in a boss 245 formed on the side wall 45. The shaft 245 has a pinion 255 (Fig. 6) secured-thereto which meshes with a rack 25I' (Fig. A plate 252 is secured to the rack 25I and has a slot 255 formed therein to receive the shaft 245 whereby the rack 25I is maintained in engagement with the pinion 255. The forward end of the rack Y I through the eye piece 255. He turns the knob 54 to bring the image of the pendulum into coincidence with the cross hair 254 on the ground glass 251. When this has been done he notes the reading on the scale 55 for the right hand lamp. After the right hand headlight has been adjusted, he places the marker I54 on the right hand lamp, and turns the collar 25l (Fig. 180.

The detent 254 disengages from the notch 245 and engages in the notch 255 (Fig. 19). The

the left hand headlight, engaging the contact 45 with the lens and manipulating the instrument 25I is pivotally connected at 254 to a lever 255 which is pivotally mounted on the sidewall by means of a pin 255. The upper end of-the lever 255 has a pin 251 rigidly mounted therein arm of the bell crank 255 has a pin 25I rigidly secured thereto which projects upwardly through a slot 252 (Figs. 5 and '1) formed in the top of the case 45 into a slot 255 formed in-the pointer When the knob 54 (Fig. 21) isrotated by the operator. it turns the pinion 255 and through the rack 25! (Fig. 5) oscillates the lever 255 which in turn oscillates the-bell crank 255 which by means of the pin 25I moves the pointer 51 over the scale 55, and since the pointer 51 is connected to the finder 224 by means of the detent 254 en-. gaged in the notch 255 or the notch245'rotation of the knob 54 also results in rotation of the finder 224. I 5

The operation is as follows: To test the right hand headlight the marker-device I54 (Fig. 1'!) is attached to the left hand headlight and adhated to bring the contact 255 (Fig. 16) against the center of the lens I55 and to position the pendulum I55 in the vertical position with its end.

22l Opposite the pointer 22!. The headlight testing instrument is then placed in front of the Y right hand headlight, as shown in Fig. 1'1, with as before to obtain the maximum intensity reading. He then turns the knob 54 (Fig. 1) to center the pendulum image on'the cross hair v254 and reads the scale for the left hand lamp.

in Fig. 21 the finder 224--and pointer 51 are shown in phantom. Assuming that the instrument has been placed in front of the right hand headlight and has been. manipulated until parallel rays 255 and 255 from the beam pass through apertures" and 51 in front diaphragm 15 and through apertures 55 and 51 in rear diaphragm 55 and are reflected by mirrors I55, I51 in the directions 251, 255 onto, the light-sensitive cell I25, when the maximum meter reading is obtained it will indicate that the instrument axis 11 is in line with the beam. Now, if the knob 54 is adjusted to point the tube 225 of the finder 224 directly atthe pendulum hanging on the other headlight,

the angle I55 formed by thecenter line 255 of the pointer 51 with the axis 11 is the horizontal angle which the beam makes with the line of travel of the vehicle, and this horizontal inclination is measured by the position of the pointer 51 (Fig. 1) on the scale 55.

Instead of employing the headlight tester as a portable instrument, it can be used with a mobile stand, if so desired. The methodof using the instrument and its construction and mode'of operation, however, remain unchanged. ,As

shown in'Figs. 25 to 25, the stand is provided with a base 215 supported on three wheels 2', 212,

215. A vertical tubular support 214 is rigidly mounted on the base 215. A second tube 215., is telescopically mounted on the tube 214 and is adapted to be vertically adjusted thereon and held in adjusted position by means of a clamp 215. The instrument support 211 has a bearing Y portion in vertically slidable' on the tube in.

The weight of the instrument and its support 211 is carried on a pulley 215 rotatably mounted in the top of the tube 215 by means of a cable 255 and counterweight 25I.

The base of the instrument has two apertures therein to receive dowel pins 252,255. The dowel Y pins 252, 255 (Fig. 26) are fixed in a lever 254 which is mounted for swinging movement on a Y pivot coincident with the front dowel 255 on a' member 255. The rear end of the lever 254 extends through an arcuate slot 255 formed in' end of a lever 255 pivoted in the support 211 at 255. An adjusting screw 251 adjustably mounted on the support 211 bearapgainst the rear' end of the lever 255. ,By turning the screw 25I the instrument can be adjusted about the horizontal pivot 281 and by swingingthe lever 284 the instrument canbe adjusted about the vertical pivot 283.

This mechanical supporting land adjusting means is employed in the same manner as previously described to adjust the instrument in the beam of the headlight to obtain the maximum reading on the meter 59, thecontact 43 being engaged with the lens 292 (Fig. 23) of the headlight. The vertical inclination is indicated on thescale 66 after adjusting the knob 63 and the horizontal inclination is read on the scale 89 7 after adjusting the knob 64, the marker 194 being attached to the other headlight in the man'- ner previously explained.

While I have described a. particular embodiment of the present invention, it will be obvious diaphragm means disposed normal ,to the axis of .said instrumentan'd provided with afplurality of apertures for admitting a plurality ofqparallel rays of light from the headlight beam, and means responsive to the light intensity of said' rays for indicating when the axis oftjtheinstrument is parallel with said headlight beam, said "contact being mounted on theli'ght-admitting end of the instrument in ffront of said diaphragm means and located on the axis of the instrument, whereby' the instrument can be manipulated universallyon said contact as a pivot.

4. A headlight testing instrument [adapt d to I be placed in thebeam' of the headlight comprisof said case and adapted to be brought into en-.

that various changes and modifications may be made in the details thereof without departing from the spirit of the present invention and the scope of the appended claims.

Having thus described my invention and in ing, a case, a single contactmounted on the front gagement with the lens of the headlight, means for selectin parallel rays from the beam, said means comprising spaced-apart diaphrag'ms mounted within said case normal to the longitudinal axis of the instrument and provided with longitudinally aiigned apertures, a light-sensitive cell having a light admitting aperture disposed phragm having aperturescorre'sponding to said apertures in said front diaphragm: and arranged in longitudinal alignment therewith so that rays from the beam entering an aperture in said front diaphragm'parallelto said axis will pass through the corresponding aperture in said sec ond diaphragm, a light-sensitive cell disposed on said axis intermediate said diaphragms, a plurality of planar mirrors mounted on said seconddiaphragm behind the apertures therein and arranged to receive the rays-passing through said apertures and to reflect the rays which pass through said apertures in said second diaphragm onto said cell, and a meter to register the response of said cell to the light reflected thereon.

2. A headlight testing instrument adapted to be placed in the beam of a headlight, comprising a front diaphragm disposed normal to the axis of the instrument and having a plurality of apertures arranged around said axis, a rear dia-' phragm spaced apart from said front diaphragm and disposed normal to said axis, said rear diaphragm having apertures corresponding to said apertures in said front diaphragm and arranged in longitudinal alignment therewith so that rays from the beam entering an aperture in said front diaphragm parallel to said axis will pass.

through the corresponding aperture in said second diaphragm, a light-sensitive cell mounted on on said axis, means to direct said selected parallel rays through said cell aperture, and a meter to register the response of said cell to the light directed thereon -said longitudinal axis of said instrument passing through the center of said lens contact, whereby the instrument can be manipulated universally on said contact as a pivot to position the instrument axis parallel to the rays of the beam as indicated by a maximum lightintensity reading on said meter.

'5. A device for testing the headlight of an automobile comprising a, portable housing, a light I receiving opening in one end of said housing adapted to receive a light beam from said headlight, means in said housing and visible from the exterior thereof for receiving the light beam en-' tering said opening and indicating when the axis of said beam coincides with the axis of the housirig, a second opening in a side wall of said houssaid front diaphragm and having a light shield disposed normal to said axis, said shield having an aperture to admit light to said cell, the center of said aperture being on said axis, a planar mirror mounted on said second diaphragm behind each aperture therein and angular-1y inclined to receive the ray which passes through the aperture and to reflect said ray through said shield aperture into said cell, and a meter to register the response of said cell to the light reflected through said shield by said mirrors.

. '3. A headlight testing instrument. having a contact adapted to be placed in engagement with the lens of the headlight, said instrument having ing adapted to receive a second light beam from an external source, and means in said housing and visible from the exterior thereof for receiving said second beam and indicating, when the axis of said second beam has a predeterminedangular relationship to the axis of said housing.

6. A headlight tester adapted to be placed in the light'beam of a headlight comprising means for indicating when the axis of the light beam of the headlight is parallel to a predetermined reference axis of the tester, an optical system associated with the tester, means for positioning the optical system at a predetermined distance ahead of the headlight, and means associated with the optical system for indicating the angular relationship of the reference axis with respect to a ray of light received by said optical system from a source laterally disposed of said tester and po- 'sitioned a definite distance ahead of said headlight. I '7. An automobile headlight testing instrument adapted to be placed in front or a headlight beam comprising a contact for contacting the hes-Li light to dispose the instrument a predetermined distance from the same, means for aligning the longitudinal axis of theinstrument with the direction of the beam projected by the headlight with which the instrument is in contact. an optical finder mounted on said instrument for angular adjustment on a vertical axis intersecting the longitudinal axis of the instrument at'a point spaced a predetermined distance from said headthem onto said intensity indicating means, said diaphragms shielding said mirrors and indicating means from the remaining rays of the headlight beam.

. 12. An apparatus for determining the direction of a headlight beam comprising a pair of 8. An automobile headlight testing instrument comprising a contact on the longitudinal axis thereof for engagement with a headlight, means for indicating when the instrument axis is in line with the beam of the headlight, an optical finder angularly adjustable on a vertical axis intersecting said instrument axis, means for indicating the angular adjustment of said finder with respect to the instrument axis, and means for aligning said finder with a marker positioned in front of the other headlight a distance equal to the distance of the intersection of said axes from said first mentioned headlight.

9. An automobile headlight testing apparatus adapted to be placed in front of one headlight, comprising a housing,- a light sensitive cell on the longitudinal axis of said housing, spaced apart diaphragms associated with the housing and disposed normal to the longitudinal axis thereof, said diaphragms having longitudinally aligned apertures for separating parallel rays from the beam of the headlight, light collecting and directing means arranged to receive said parallel rays and to direct and focus the same onto said cell, a meter for registering the electrical response of said cell, an optical finder mounted within diaphragms for positioning in front of a headlight, said diaphragms being arranged one behind the other and provided with aligned apertures whereby to separate parallel shafts of light from said beam and permit passage of said shafts therethrough, light intensity indicating means intermediate said diaphragms, planar mirrors arranged to receive said parallel shafts of light, and adjustable means for individually positioning said planar mirrors relative to the apertures of the diaphragms and the light intensity indicating means to reflect the shafts of light admitted by the apertures of the diaphragms onto said light intensity indicating means.

13. A device for testing the lateral adjustment of an automobile headlight, which includes a housing having an opening adapted to be manually positioned in opposition to the lens of a headlight, said housing being provided with externally-observable means for indicating when it is also positioned in a definite relation to the said housing for angular adjustment about a vertical axis intersecting the longitudinal axis of the housing at right angles, the side wall of said housing having an aperture aligned with said finder, and an indicator for indicating the angular adjustment of said finder with respect to the longitudinal axis of the housing whereby said housing can. be positioned with the longitudinal Y axis thereof in line with the headlight beam as indicated by the maximum reading on said meter and said finder can be adjusted to sight a marker placed in front of the other headlight to obtain a measurement of the lateral aim of said beam.

10. An automobile headlight testing instrument comprising, a case having a contact for engaging the lens of one headlight, handles on said case for enabling an, operator to manipulate the case on said contact as a pivot to align the axis of the case with the beam of said headlight,

an optical finder in said case adjustable for sighting a marker disposed in front of the other headlight, means to adjust-said finder including an adjusting-member adjacent one of said han: dles, a scale on said case disposed at one side of the axis of the case, and an indicator adjustable with said finder andcooperating with said scale for registering the horizontal inclination of the beam of said first mentioned headlight relative to the inclination of the beam of the other headlight, said indicator being so connected to said finder that the indicator is at zero on said scale when the sight line of said finder is at right angles to the case axis.

11. An apparatus for determining the directionv "hot spot" of the beam projected through said opening by said headlight, an externally-oberally with respect to the longitudinal axis of the automobile.-

14. A device for testing the lateral adjustment of an automobile headlight, which includes a housing having an opening adapted to be manually positioned in opposition to the lens of a headlight, said housing being provided with ex-' ternally-observable means for indicating when itis also positioned in a definite relation to the hot spot of the beam projected through said opening by said headlight, an externally-observable screen in said housing, a second opening in saidhousing, an optical system in said housing aligned with said second opening and so positioned that, when said housing is positioned in said relation to said headlight and said hot spot, a beam of light originating at a point to one side of and at a definite distance ahead of said headlight lens will pass through said optical system and impinge upon an indicated part of said screen when the headlight beam is projected in the desired direction laterally with respect to the longitudinal axis of the automobile, both said means and said screen being so positioned as to be observable from the same position of observation.

15. A device for testing the adjustment of an automobile headlight, which includes a housing having an opening adapted to be manually po-1 projected through said opening, an externallyobservable target, a second opening in said housing, an optical system in said housing, the optical axis of which passes through said second opening and is also so directed as to direct a beam of light from a source positioned to one side of and at a predetermined distance in front of the headlight lens onto an indicated part of said target when the headlight beam is projected in the desired direction laterally with respect to the longitudinal axis of the automobile.

16. A device for testing the headlight of an automobile comprising a portable housing, a light receiving opening in one end of said housing adapted to receive a light beam from said headlight, means adapted to be manually positioned against the lens of said headlight to .position said opening in opposition to said lens, means in said housing and visible from the exterior thereof for receiving the light beam entering said opening and indicating when the axis of said beam coincides with the axis of the housing, a second opening in a side wall of said housing adapted to receive a second light beam from an external source, and means in said housing and visible from the exterior thereof for receiving said second beam and indicating when the axis of said second beam has a predetermined angular relationship to the axis of said housing.

17. A device for testing the headlight of an automobile comprising a portable housing, a light receiving opening in one end of said housingadapted to receive a light beam from said headlight, means in said housing and visible from the exterior thereof for receiving thelight beam entering said opening and indicating when the axis of said beam coincides with the axis of the housing, said means comprising an electricallight responsive element,. a second opening in a side wall of said housing adapted to receive a second light beam from an external source, and means including a screen in said housing and visible from the exterior thereof for receiving said second beam and indicating when the axis an indicator releasably connected to said finder for registering the angular position of said optical finder with respect to the longitudinal axis of saidsupport, and means operatively interconnecting said indicator and said optical finder in two positions of said finder, one for sighting to the left, the other to the right, said interconnecting means being operable to disconnect the indicator from thefinder when the finder is moved from one position to the other. I

20. An apparatus for determining the lateral adjustment of an automobile headlight comprising a support adapted to be placed in front of one headlight with the longitudinal axis of the support aligned with the headlight beam, an optical finder mounted on the support for rotation on a vertical axis through an angle of approximately 180 to dispose said finder in diametrically opposite positions on the support, a

pointer releasably connected to said finder and movable over a scale mounted on the support to indicate the angular position of said finder with respect to'the longitudinal axis of said support, means for connecting said pointer and said finder for movement together when said finder is disposed in either one of said diametrically op- -posite positions, and means for moving said pointer to adjust said finder for sighting the finder on a marker placed in front of the other headlight of the automobile, said connecting means being operable to disconnect the pointer ,from the finder when the finder is moved from one position to the other. I

21. An apparatus for testing the vertical and lateral adjustment of an automobile headlight comprising a support adapted to be positioned in front of one headlight of the automobile with the longitudinal axis of the support aligned with the headlight beam, spaced diaphragms on said support having longitudinally aligned apertures of said second beam has a predetermined angular relationship to the axisof said housing.

18. A device for testing the headlight of an automobile comprising a portable housing, a light receiving opening in one end of said housing adapted to receive a light beam from said headlight, means adapted to be manually positioned against the lens of said headlight to position said opening in oppositionto saidlens,

means in said housing and visible from the exterior thereof for receiving the light beam entering said opening and indicating when the axis (if said beam coincides with the axis of the housing, said means comprising an electrical light responsive element, a second opening in a side wall of said housing adapted to receive asecond light beam from an external source, and means in said housing and visible from the exterior thereof for receiving said second beam and in-- dicating when the axis of said second beam has a predetermined angular relationship to the axis of said housing, said means including a reflector for receiving light from said second opening and adapted to reflect said light on an externally observable screen.

19. An automobile headlight testing apparatus for determining the direction in which a headlight is projecting its beam, comprising a .sup-

' port adapted to be positioned in front of one headlight with the longitudinal axis of the support aligned with the headlight beam, an optical finder mounted on said support, said optical finder being adjustable for sighting on a marker for admitting rays from the beam parallel to the axis of the support,'means on said support responsive to the rays of the headlight beam passing through the aligned apertures of said diaphragms for indicating the amount of light passing through said apertures, means including a leveling device on said support for indicating the vertical inclination of the longitudinal axis of said support, means for measuring the lateral deviation of the longitudinal axis of said support with respect to the line of travel of the automobile when the longitudinal axis of the support is aligned with the headlight beam including an optical finder on the support, means for adjusting said finder for sighting a marker positioned in front of the other headlight of the automobile, and means for indicating the angular position of said finder with respect to the direction of the axis of the support when said finder .is sighted against said marker.

22. An apparatus for testing the vertical and horizontal adjustment-of an automobile headlight comprising a housing having a contact thereon aligned with the longitudinal axis of the housing, two handles on said housing. for enabling an operator to hold the housing with said contact in engagement with the lens of the headlight and to manipulate the'housing with said contact as a pivot to position the longitudinal axis of the housing in parallelism with the headlight beam, means associated with said housing for indicating when the longitudinal axis thereof is parallel with the headlight beam, means including a leveling'device within said housing for measuring the vertical inclination of the longitudinal axis of said housing when the longitudinal axis of the housing is parallel with the headlight beam, means for measuring the horizontal deviation of the longitudinal axis of said housing with respect to the line of travel of the automobile when the longitudinal axis of the housing is aligned with the headlight beam including an optical finder within said housing, means for adjusting said finder from the exterior of said housing for sighting a marker positloned in front of the other headlight of the automobile, and means for indicating the angular position of said finder with respect to the longitudinal axis of said housing when said finder is sighted against said marker.

23. An apparatus for determining the direction in which a headlight of an automobile is projecting its beam comprising a support adapted to be placed in front of the headlight with the longitudinal axis of the support aligned with the headlight beam, an optical finder mounted on the support for rotation on a vertical axis intersecting the longitudinal axis of said support through an angle of approximately 180 to dispose said finder in diametrically opposite positions on the support, a pointer releasably con- 18 ing when the finder is sighted against said marker.

25. A headlight testing instrument adapted to be placed in the beam of the headlight and having a case containing testing mechanism responsive to changes in the light intensity as determined by changes in the positionof said case relative to the headlight beamv for indicating when the axis of said beam coincides with the axis of the instrument, the case being provided with a plurality of apertures to admit parallel shafts of light from the beam to the interior of said case, means within the case for intercepting parallel shafts of light admitted through the apertures for actuating the testing mechanism, and a contact composed of slip resisting material mounted in fixed position on said case centrally with respect to the apertures and coincident with the longitudinal axis of the instrument, said contact being adapted to engage the headlight at a single point and to permit the instrument nected to said finder and movable over a scale mounted on the support at one side of the longitudinal axis of the support to indicate the angular position of said finder with respect to the longitudinal axis of said support, means for connecting said pointer and said finder for move- .ment together when said finder is disposed in either one of said diametrically opposite positions, and means for moving said pointer to adjust said finder for sighting the finder on a marker disposed in front of the other headlight of the automobile.

24. An apparatus for testing the vertical and the horizontal adjustment of an automobile headlight comprising, a housing having a contact thereon aligned with the longitudinal axis of the housing, two handles on said housing for enabling an operator to hold the housing with said contact in engagement with the lens of the headlight and to manipulate the housing with said contact as a pivot to position the longitudinal axis of the housing in parallelism with the headlight beam, means associated with said housing for indicating when the longitudinal axis thereof is parallel with the headlight beam, means including an adjustable leveling device within said housing for measuring the vertical inclination of the longitudinal axis of said housing when the lon tudinal axis of the housing is parallel with the headlight beam, means exterior of said housing and adjacent one of said handles for adjusting said leveling device to horizontal position,'a window formed in each side of said housing, means for measuring the horizontal deviation of the longitudinal axis of said housing with respect to the line of travel of the automobile when the longitudinal axis of the housing is aligned with the headlight beam, including an optical finder within said housing adapted to be placed for sighting through either of said windows, means adjacent the other of said handles for adjusting said finder from the exterior of said housing for sighting through either of said windows a marker positioned in front of the other headlight of the automobile, and means for indicatingthe angular position of said finder with respect to the longitudinal axis of said housto be manipulated universally on said contact as a pivot while said contact is maintained in engagement with the lens to position the instrument axis parallel to the shafts of light admitted through the apertures. I

26. An automobile headlight testing apparatus comprising, a housing adapted to be placed in front of one headlight with the longitudinal axis of said housing aligned therewith, said housing being provided with a window on each side, an

optical finder selectively rotatable into alignment with either of said windows for sighting a marker placed in front of the other headlight through the selected window, a pointer connected to said finder, means for releasing said connection to permit said selective rotation of the finder relative to the pointer, means for operatively connecting said pointer to said finder when said finder is positioned for sighting through either of said windows, and two scales at one end of said housing, one of said scales being disposed at one side of the longitudinal axis of said housing and cooperating with an index line on said pointer for measuring the horizontal aim of the left headlight of an automobile, and the other scale being disposed at the other side of the longitudinal axis of said housing and cooperating with .a second index line on said pointer for measuring the horizontal aim of the right headlight of an automobile, the connection between said finder and said pointer being suchthat each of said index lines is at zero on its scale when the sight line of the finder is normal to said housing axis.

27. A headlight testing instrument adapted to be placed in the' beam of a headlight and having a case containing testing mechanism capable of indicating changes in intensity of light impressed thereon as determined by changes in the position of saidcase relative to the head'- light beam to indicate when the axis of said beam coincides with the axis of the case, said case being provided with a plurality of apertures for admitting shafts of light from the beam to the interior of said case, means within the case for intercepting the shafts of light admitted through axis of the headlight beam as indicated by a maximum light intensity indicated by said testvice a predetermined distance ahead of the headlight, and means associated with said sighting device for indicating when. the device is aligned with a marker positioned a predetermined, distance in front of the other headlight of the automobile, whereby an imaginary plane is established between said indicating means and said marker to which plane the direction of the beam of the headlight to be tested can be reierred to for measurement oi its aim.

29. A headlight tester adapted to be placed in the light beam of one headlight of an automobile, comprising means for indicating when the axis of the light beam of the headlight is parallel to a predetermined reference axis oi the tester, an adjustable lateral sighting device associated with said tester, means for positioning said device a predetermined distance ahead of the headlight, means associated with said sighting device for indicating when the device is aligned with a marker positioned a predetermined distance in front or the other headlight oi the automobile, whereby an imaginary plane is established between said indicating means and said marker to which plane the direction of the beam of the headlight to be tested can be referred to for measurement of its aim, and means asso- 20 I ciated with the tester and the sighting device for measuring the angular disposition oi the reference axis of the tester with respect to said imaginary plane.

30. A headlight tester adapted to be placed in the light beam or one headlight of an automobile, comprising means for indicating when the axis of the light beam of the headlight is aligned with a predetermined reference axis of the tester, a sighting device associated with said tester and angularly adjustable on a vertical axis intersecting said tester axis at a predetermined distance from the front of the tester, means for indicating when said sighting device is aligned with a target positioned in front of the other headlight of, the automobile a. distance substantially equal to the distance 0! the intersection of said vertical axis and said tester axis from the first mentioned headlight, and means for indicating the angular relationship of said sighting device with respect to thepredetermined reference axis of the tester.

31. A headlight tester adapted to be placed in the light beam of a headlight, comprising means for indicating when the axis of the light beam of the headlight has a predetermined relationship to a predetermined reference axis of the tester, an optical system associated with the tester, means for positioning the optical system at a predetermined distance ahead of the headlight, and means associated with the optical system for indicating the angular relationship of the reference axis with respect to a ray of light received by said optical system from a source laterally disposed of said tester and positioned a definite distance ahead of said headlight.

HERBERT GLENN HOLMES. 

